my lfs owner who has his BSc in marine biology and botany has told me that the most important thing with gonipores is lighting and i dont specificlly feed my goinys i use frozen baby brine twice a week for the whole tank and marine snow attached is a pic of two of my gonys the green one is most impressive and as i only just took this pic couldnt get it fully open with out the halide on its more then 7 inches across and 6 inches high when fully opened but rock base is only bout 5 inches across and 3 inches hiesght wise
good luck and happy tanking